1. Field of the Invention:
The present invention relates to a machine tool, and more particularly to a machine tool for use as a tapping machine, a drilling machine, or the like.
2. Description of the Relevant Art:
One known machine tool having a spindle device for use as a tapping machine or a drilling machine to machine a workpiece is disclosed in Japanese Patent Publication No. 60-44101 published Oct. 1, 1985 (claiming Convention priority under U.S. Patent Application No. 142625 filed April 22, 1980, now U.S. Pat. No. 4,384,397).
The disclosed machine tool includes a cross-slide table movable transversely and a feed table mounted on the cross-slide table and movable in a direction normal to the direction in which the cross-slide table is movable, i.e., a direction toward and away from a workpiece. Vertical guide rails are mounted on the feed table, and a vertically movable spindle table is mounted on the guide rails, with a spindle device installed on the spindle table. The spindle device is positionally adjustable with respect to a position where the workpiece is to be machined, by moving the above various tables.
In the above disclosed machine tool, the three tables are movable linearly in two horizontal directions and one vertical direction for varying the position of the spindle device three-dimensionally.
The vertically movable spindle table engages the vertical guide tables which project upwardly from the spindle table. A drive motor and a cylinder unit for vertically moving the spindle table are disposed above the guide rails. The conventional machine tool of such a construction is of necessity large in outer profile, particularly vertical dimensions thereof, and has its center of gravity at a high position.